Email systems are configured to send and receive emails on behalf of registered users that pay for such services. Generally, email systems do not allow non-registered users or users that do not pay for such services, to send email messages to other recipients on their behalf. Open relay servers which do not require paid subscriptions allow users to send such emails. However, these open relay servers and associated email systems do not provide rich scanning features such as anti-spam and anti-malware services. In certain circumstances, registered users of an email system may send messages to non-registered users or users of such open relay systems. These messages may require a recipient to reply to the message, for example where the registered user is a company inquiring about business opportunities with potential customers. However, if the recipient is not a registered user of the email system, but rather utilizes an open relay system, a reply or forward of the original email may not have undergone content scanning, filtering or even encryption. This may compromise the security of the original sender's mailbox as well as making the registered user's email account susceptible to malware and spam. It is with respect to these and other considerations that the present improvements have been needed.